A person who existentially resembles a speck of dry shit hanging from an ass hair of a gorilla. esp. when said person realizes this fact and sharply hones it's "skill" (i.e. propensity) in the execution of self-serving, smarmy, meaningless, petty vendettas for short term gain, which all results in a net tally of gains which equals to zero. Not even gaining an ego boost, when you consider that their devolved impersonation of an ego is not of enough value to apply. Their biggest asset, if not their only one, tends to be their "skill" (i.e. propensity) to cheat. They are metaphorically refered to as ants due to their common abundance, and refered to as being urinated on ("piss-") due to their general insignificance and lack of impact.

"Hmm, seems some lamer lamed some abandoned game server with some ancient cheat programs"
"Eh. What do you expect from these script-kiddie pissants?"

"Some pissant flooded the forum"
"Did you say something?"
"Huh? Oh anyways, what was I talking about?
"About the size of movie theatres"
"Oh right, the position of ..."

A pissant is described by Kurt Vonnegut in his novel, Cat's Cradle, as follows:
"A pissant is somebody who thinks he's so damn smart, he can never keep his mouth shut. No matter what anybody says, he's got to argue with it. You say why you like something, and, by God, he'll tell you why you're wrong to like it. A pissant does his best to make you feel like a boob all the time. No matter what you say, he knows better."